Applications with minimal power requirements can use the #16869 sealed rechargeable battery. This compact, sealed rechargeable, 12 V battery is optimized for use with a CR200X datalogger and the ENC200 Enclosure. The 16869 has an 0.8 Ahr (800 mAhr) capacity.
The 15598 powers the clock and SRAM when the primary 12 Vdc power supply is not connected. This 3 V lithium coin cell battery needs to be periodically replaced. Campbell Scientific recommends replacing the battery every five years.